1. Field of the Invention
The present invention relates generally to an improved form of the flexible lances and systems disclosed in the above related applications. More particularly, it relates to such a flexible lance and system in which performance of the lance and system is enhanced in the areas of strength and flexibility, durability, fluid delivery at high flow and pressure, access to a difficult to access gemometry and locomotion within the difficult to access geometry.
2. Description of the Prior Art
The flexible lances and systems in the above related applications represent a substantial improvement in the art for accessing and cleaning a difficult to access geometry, such as in sludge removal on the secondary side of pressurized water reactor (PWR) steam generators in the nuclear power industry. However, certain elements of the design disclosed in those applications are unforeseen characteristics of the steam generators and the sludge deposits in them resulted in less than optimum performance of those flexible lance and system designs, including strength, durability and flexibility of the flexible lance, the volume and pressure of water delivered through the lances and tight intertube clearance. In the previous designs, the systems performed their operations on the steam generators while positioned on the central blowdown pipe. This operation mode limited access to intertube columns near the manhole due to the length of the transporter. Viewing the "back side" of the tall sludge pile existing in the steam generator was difficult due to the low operating elevation of the system transporter.